http-errors 2.0.0: createError

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify createError in pkg:npm/http-errors@2.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/http-errors@2.0.0
Demonstrate these symbols/APIs:
  - createError

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:9e00c147f97de8f2856d0c20c9c01601bf0e1085f62192757f77e3fcbff4d9cf","contract":["assert createError creates 4xx HttpError with status, statusCode, name, and expose true by default","assert createError creates 5xx HttpError with expose false by default","assert createError attaches custom properties and respects custom expose override","assert createError wraps existing Error preserving original message and assigning status","assert named error constructors create corresponding HttpError instances","assert isHttpError identifies HttpError instances and rejects standard Errors or non-errors"],"goal":"verify createError in pkg:npm/http-errors@2.0.0","kind":"HOW","packages":["pkg:npm/http-errors@2.0.0"],"schemaVersion":1,"symbols":["createError"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/http-errors@2.0.0"],"schemaVersion":1,"subject":"pkg:npm/http-errors@2.0.0","symbols":["createError"],"verifierAdapter":"node-typescript@1"}

const createError = require('http-errors');

function makeHttpError(...args) {
  return createError(...args);
}

function makeClientError(status, message, props) {
  if (typeof status !== 'number' || status < 400 || status >= 500) {
    throw new Error('Status code must be 4xx');
  }
  if (props !== undefined) {
    return createError(status, message, props);
  }
  if (message !== undefined) {
    return createError(status, message);
  }
  return createError(status);
}

function makeServerError(status, message, props) {
  if (typeof status !== 'number' || status < 500 || status >= 600) {
    throw new Error('Status code must be 5xx');
  }
  if (props !== undefined) {
    return createError(status, message, props);
  }
  if (message !== undefined) {
    return createError(status, message);
  }
  return createError(status);
}

function wrapError(status, originalError) {
  return createError(status, originalError);
}

function checkHttpError(err) {
  return createError.isHttpError(err);
}

module.exports = {
  createError,
  makeHttpError,
  makeClientError,
  makeServerError,
  wrapError,
  checkHttpError,
};

{
  "name": "sample-http-errors",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-http-errors",
      "version": "1.0.0",
      "license": "MIT-0",
      "dependencies": {
        "http-errors": "2.0.0"
      }
    },
    "node_modules/depd": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/depd/-/depd-2.0.0.tgz",
      "integrity": "sha512-g7nH6P6dyDioJogAAGprGpCtVImJhpPk/roCzdb3fIh61/s/nPsfR6onyMwkCAR/OlC3yBC0lESvUoQEAssIrw==",
      "license": "MIT",
      "engines": {
        "node": ">= 0.8"
      }
    },
    "node_modules/http-errors": {
      "version": "2.0.0",
      "resolved": "https://registry.npmjs.org/http-errors/-/http-errors-2.0.0.tgz",
      "integrity": "sha512-FtwrG/euBzaEjYeRqOgly7G0qviiXoJWnvEH2Z1plBdXgbyjv34pHTSb9zoeHMyDy33+DWy5Wt9Wo+TURtOYSQ==",
      "license": "MIT",
      "dependencies": {
        "depd": "2.0.0",
        "inherits": "2.0.4",
        "setprototypeof": "1.2.0",
        "statuses": "2.0.1",
        "toidentifier": "1.0.1"
      },
      "engines": {
        "node": ">= 0.8"
      }
    },
    "node_modules/inherits": {
      "version": "2.0.4",
      "resolved": "https://registry.npmjs.org/inherits/-/inherits-2.0.4.tgz",
      "integrity": "sha512-k/vGaX4/Yla3WzyMCvTQOXYeIHvqOKtnqBduzTHpzpQZzAskKMhZ2K+EnBiSM9zGSoIFeMpXKxa4dYeZIQqewQ==",
      "license": "ISC"
    },
    "node_modules/setprototypeof": {
      "version": "1.2.0",
      "resolved": "https://registry.npmjs.org/setprototypeof/-/setprototypeof-1.2.0.tgz",
      "integrity": "sha512-E5LDX7Wrp85Kil5bhZv46j8jOeboKq5JMmYM3gVGdGH8xFpPWXUMsNrlODCrkoxMEeNi/XZIwuRvY4XNwYMJpw==",
      "license": "ISC"
    },
    "node_modules/statuses": {
      "version": "2.0.1",
      "resolved": "https://registry.npmjs.org/statuses/-/statuses-2.0.1.tgz",
      "integrity": "sha512-RwNA9Z/7PrK06rYLIzFMlaF+l73iwpzsqRIFgbMLbTcLD6cOao82TaWefPXQvB2fOC4AjuYSEndS7N/mTCbkdQ==",
      "license": "MIT",
      "engines": {
        "node": ">= 0.8"
      }
    },
    "node_modules/toidentifier": {
      "version": "1.0.1",
      "resolved": "https://registry.npmjs.org/toidentifier/-/toidentifier-1.0.1.tgz",
      "integrity": "sha512-o5sSPKEkg/DIQNmH43V0/uerLrpzVedkUh8tGNvaeXpfpuwjKenlSox/2O/BTlZUtEe+JG7s5YhEz608PlAHRA==",
      "license": "MIT",
      "engines": {
        "node": ">=0.6"
      }
    }
  }
}

{
  "name": "sample-http-errors",
  "version": "1.0.0",
  "description": "Minimal clean-room sample verifying createError in http-errors",
  "main": "index.js",
  "license": "MIT-0",
  "dependencies": {
    "http-errors": "2.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify createError in pkg:npm/http-errors@2.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/http-errors@2.0.0"
  ],
  "symbols": [
    "createError"
  ]
}

import assert from 'node:assert';
import createError from 'http-errors';
import {
  makeHttpError,
  makeClientError,
  makeServerError,
  wrapError,
  checkHttpError,
} from '../index.js';

// 1. assert createError creates 4xx HttpError with status, statusCode, name, and expose true by default
const notFoundErr = createError(404, 'Resource not found');
assert.strictEqual(notFoundErr.status, 404);
assert.strictEqual(notFoundErr.statusCode, 404);
assert.strictEqual(notFoundErr.name, 'NotFoundError');
assert.strictEqual(notFoundErr.message, 'Resource not found');
assert.strictEqual(notFoundErr.expose, true);
assert.ok(notFoundErr instanceof Error);
assert.ok(notFoundErr instanceof createError.HttpError);
assert.ok(notFoundErr instanceof createError.NotFound);

const helperClientErr = makeClientError(403, 'Forbidden access');
assert.strictEqual(helperClientErr.status, 403);
assert.strictEqual(helperClientErr.statusCode, 403);
assert.strictEqual(helperClientErr.name, 'ForbiddenError');
assert.strictEqual(helperClientErr.expose, true);

// 2. assert createError creates 5xx HttpError with expose false by default
const serverErr = createError(500, 'Internal database failure');
assert.strictEqual(serverErr.status, 500);
assert.strictEqual(serverErr.statusCode, 500);
assert.strictEqual(serverErr.name, 'InternalServerError');
assert.strictEqual(serverErr.message, 'Internal database failure');
assert.strictEqual(serverErr.expose, false);
assert.ok(serverErr instanceof createError.InternalServerError);

const helperServerErr = makeServerError(503, 'Service unavailable');
assert.strictEqual(helperServerErr.status, 503);
assert.strictEqual(helperServerErr.expose, false);

// 3. assert createError attaches custom properties and respects custom expose override
const customErr = createError(400, 'Invalid parameter payload', {
  code: 'ERR_INVALID_PARAM',
  field: 'username',
  expose: false,
});
assert.strictEqual(customErr.status, 400);
assert.strictEqual(customErr.statusCode, 400);
assert.strictEqual(customErr.name, 'BadRequestError');
assert.strictEqual(customErr.code, 'ERR_INVALID_PARAM');
assert.strictEqual(customErr.field, 'username');
assert.strictEqual(customErr.expose, false);

const helperCustom = makeHttpError(422, 'Unprocessable entity', {
  details: [{ field: 'email', reason: 'invalid format' }],
});
assert.strictEqual(helperCustom.status, 422);
assert.strictEqual(helperCustom.statusCode, 422);
assert.deepStrictEqual(helperCustom.details, [{ field: 'email', reason: 'invalid format' }]);
assert.strictEqual(helperCustom.expose, true);

// 4. assert createError wraps existing Error preserving original message and assigning status
const originalError = new Error('Connection refused');
const wrapped = wrapError(502, originalError);
assert.strictEqual(wrapped.status, 502);
assert.strictEqual(wrapped.statusCode, 502);
assert.strictEqual(wrapped.message, 'Connection refused');
assert.strictEqual(wrapped.expose, false);
assert.strictEqual(wrapped, originalError);

// 5. assert named error constructors create corresponding HttpError instances
const badRequest = new createError.BadRequest('Missing required headers');
assert.strictEqual(badRequest.status, 400);
assert.strictEqual(badRequest.statusCode, 400);
assert.strictEqual(badRequest.name, 'BadRequestError');
assert.strictEqual(badRequest.message, 'Missing required headers');
assert.strictEqual(badRequest.expose, true);
assert.ok(badRequest instanceof createError.BadRequest);
assert.ok(badRequest instanceof createError.HttpError);
assert.ok(badRequest instanceof Error);

const unauthorized = new createError.Unauthorized('Bearer token required');
assert.strictEqual(unauthorized.status, 401);
assert.strictEqual(unauthorized.statusCode, 401);
assert.strictEqual(unauthorized.name, 'UnauthorizedError');
assert.strictEqual(unauthorized.expose, true);

// 6. assert isHttpError identifies HttpError instances and rejects standard Errors or non-errors
assert.strictEqual(createError.isHttpError(notFoundErr), true);
assert.strictEqual(createError.isHttpError(badRequest), true);
assert.strictEqual(createError.isHttpError(wrapped), true);
assert.strictEqual(checkHttpError(helperServerErr), true);

assert.strictEqual(createError.isHttpError(new Error('plain error')), false);
assert.strictEqual(createError.isHttpError('string error'), false);
assert.strictEqual(createError.isHttpError(null), false);
assert.strictEqual(createError.isHttpError(undefined), false);
assert.strictEqual(createError.isHttpError({ status: 500 }), false);

console.log('All http-errors contract assertions passed.');